Assessment Of Brain Atrophy Research Articles

Optical coherence tomography in multiple sclerosis

Axonal distribution within the retinal nerve fiber layer (RNFL) measured by optical coherence tomography (OCT) correlates with axonal viability and integrity. To investigate correlations between RNFL and MRI measures of axonal loss in MS patients. Fifty one remitting-relapsing MS patients, 20 with a history of optic neuritis (MS-ON), 31 without optic neuritis (MS N-ON), and 12 healthy control subjects (HC) were included in the study. RNFL was measured by OCT and brain atrophy was assessed by MRI. The average RNFL in the affected eye (AE) in the MS-ON group was significantly lower than the RNFL in the MS N-ON (p = 0.01) and in HC (p = 0.01). The average RNFL in the unaffected eye (UE) and RNFL in MS N-ON were also lower than HC, but this value did not achieve significance. In MS N-ON a lower average RNFL was associated with an increased T1 lesion volume (p = 0.03) and T2-lesion volume (p = 0.001). The RNFL in MS N-ON was also associated with a reduction of BPF and %gm fraction (p = 0.01, p = 0.02 respectively). In MS-ON there was a much weaker, non-significant correlation between RNFL thickness and T1, T2 volume, BPF, %gm and %wm fractions that might have resulted from a pronounced post-inflammatory local optic nerve atrophy in AE. The RNFL measured by OCT may be useful as a surrogate marker for assessment of brain atrophy in MS.

Different Atrophic Patterns in Early- and Late-Onset Alzheimer’s Disease and Evaluation of Clinical Utility of a Method of Regional z-Score Analysis Using Voxel-Based Morphometry

Background/Aims: We evaluated the differential patterns of brain atrophy in early- and late-onset Alzheimer’s disease (AD) by measuring regional z-scores of voxel-based morphometry and assessed the availability of the method for clinical use. Methods: The first 50 patients with probable AD were compared to 83 age-matched control subjects to identify the brain atrophy. Regions of interest were set in the areas showing z-scores >4. To find substantial differences in the atrophy pattern, principal component analysis was performed. The second group of 56 patients with memory complaints entered the study for evaluation of the clinical use of the model. Results: The centers of the regions of interest were the amygdala, anterior hippocampi, posterior hippocampi, temporal cortices and subcallosal cortex, and left posterior cingulate cortex (PCC). Eigenvectors of the temporal cortices and left PCC showed counter-directions to those of patient age, suggesting that patients with younger onset age were preferentially associated with atrophy of those regions. Differential analyses of the second group showed high availability for the detection of abnormal brain atrophy in people with subjective memory complaints. Conclusion: AD with earlier onset is preferentially related to PCC and temporal lobe atrophy. Voxel-based morphometry can be statistically analyzed, and this method has the potential for bias-free assessment of brain atrophy.

Clinical and conventional MRI predictors of disability and brain atrophy accumulation in RRMS

To assess the value of clinical and MRI variables in predicting short-term brain atrophy accumulation and clinical evolution in a large cohort of patients with RRMS, we studied a cohort of 548 patients, previously enrolled as a placebo arm of a 14-month, double-blind trial of oral glatiramer acetate (GA). A logistic regression model with EDSS progression as the dependent variable was built to assess baseline clinical and MRI variables associated with clinical worsening during follow-up. In 466 patients with complete central brain atrophy assessment, another linear regression model with percentage central brain volume change (PCBVC) as the dependent variable was built to assess baseline clinical and MRI variables associated with atrophy development.A total of 80 patients (15%) had EDSS progression over the follow-up period. Factors independently predicting the probability to have a clinical progression were lower EDSS (OR = 0.78, 95% CI = 0.62-0.97 p = 0.02) and higher T2 LL (OR = 1.022, 95% CI = 1.006-1.038, p = 0.007) at baseline. In the 466 patients with atrophy assessment, PCBVC declined, on average, by -2.0% (SD = 2.8) (p < 0.001) over the follow-up. The multivariate PCBVC analysis revealed that the PCBVC decrease was independently correlated with higher EDSS (p = 0.03) and T2 LL (p = 0.005) at baseline. The squared correlation coefficients of the composite scores made up of EDSS and T2 LL considered together were able to explain only 3 % of the variance in disability progression and only 4 % of the variance of PCBVC.In RRMS patients, clinical and conventional MRI findings at baseline only modestly predict shortterm accumulation of brain atrophy and disability. These data confirm the need to develop clinical and MRI measures more sensitive towards the more disabling aspects of the disease.

Measuring Brain Atrophy in Multiple Sclerosis

The last decade has seen the development of methods that use conventional magnetic resonance imaging (MRI) to provide sensitive and reproducible assessments of brain volumes. This has increased the interest in brain atrophy measurement as a reliable indicator of disease progression in many neurological disorders, including multiple sclerosis (MS). After a brief introduction in which we discuss the most commonly used methods for assessing brain atrophy, we will review the most relevant MS studies that have used MRI-based quantitative measures of brain atrophy, the clinical importance of these results, and the potential for future application of these measures to understand MS pathology and progression. Despite the number of issues that still need to be solved, the measurement of brain atrophy by MRI is sufficiently precise and accurate. It represents one of most promising in vivo measures of neuroaxonal degeneration in MS, and it should be used extensively in the future to assess and monitor pathological evolution and treatment efficacy in this disease.

Microglial imaging with positron emission tomography and atrophy measurements with magnetic resonance imaging in multiple sclerosis: a correlative study

The objectives of the present study were to assess brain atrophy in multiple sclerosis (MS) patients during different disease stages and to investigate by PET and [11C]PK11195, a marker of microglial activation, the relationship between inflammation, atrophy and clinically relevant measures. Eight healthy subjects and 22 MS patients were included. Semiquantitative [11C]PK11195 uptake values, with normalization on cortical grey matter, were measured for magnetic resonance imaging T2- and T1-lesions and normal appearing white matter (NAWM). As atrophy index we used the ratio of the amount of white and grey matter divided by the ventricular size, using an optimized a priori based segmentation algorithm (SPM99). Atrophy was significantly greater in MS patients compared to age-matched controls. A significant correlation was found between brain atrophy and both disease duration and disability, as measured with the Expanded Disability Status Scale. For NAWM, [11C]PK11195 uptake increased with the amount of atrophy, while T2-lesional [11C]PK11195 uptake values decreased according to increasing brain atrophy. The present study suggests that brain atrophy, correlating with disease duration and disability, is directly related to NAWM and T2-lesional inflammation as measured by microglial activation.

Dehydration confounds the assessment of brain atrophy

Computerized brain volumetry has potential value for diagnosis and the follow-up evaluation of degenerative disorders. A potential pitfall of this method is the extent of physiologic variations in brain volume. The authors show that dehydration and rehydration can significantly change brain volume: lack of fluid intake for 16 hours decreased brain volume by 0.55% (SD, +/-0.69), and after rehydration total cerebral volume increased by 0.72% (SD, +/-0.21).

Assessment of brain atrophy in elderly subjects with diabetes mellitus by computed tomography

Background:Several studies have shown cognitive functional impairment in elderly subjects with diabetic mellitus (DM). However, there have been few studies on the image of the brain in DM subjects.Methods:To assess brain atrophy in elderly DM subjects their brain images were evaluated using computed tomography (CT). Thirty‐eight DM subjects and 17 non‐DM subjects (60–80 years of age) were included. The mean age for DM subjects and control subjects were 71.2 ± 5.5 years and 71.6 ± 5.7 years, respectively. For assessment of brain CT images, five indices (Evan’s ratio, inverse cella media index, width of the third ventricle, the width of the temporal horns on both sides, and the maximal width of the Sylvian fissure at insula on both sides) were used.Results:Evan’s ratio and the temporal horns on both sides in DM subjects were significantly larger than those in control subjects. Further analysis within DM subjects, who were divided into three groups according to their therapy (insulin, medication, and diet therapy), showed that insulin‐treated subjects had the widest temporal horns.Conclusions:The current study suggested that elderly DM subjects had brain atrophy compared with age‐matched non‐DM subjects. The insulin‐treated group had the highest amount of brain atrophy of the DM subjects.

Interobserver variability in CT assessment of brain atrophy.

To assess interobserver variability in estimation of brain atrophy based on CT, four neuroradiologists examined CT brain images of 150 consecutive patients without focal lesions. An independent neuroradiologist made the following quantitative measurements: frontal horn index, subarachnoid space area and the ratio between subarachnoid space area and inner skull space area. Level of agreement was fair for the presence (k = 0.24), slight for the degree (mild, moderate, severe) (k = 0.24) and moderate for the type (cortical, subcortical, mixed) of atrophy (k = 0.59). There was a highly significant correlation between the number of observers agreeing and quantitative measurements. We concluded that neuroradiologists' subjective estimation of brain atrophy alone is not reliable. Quantitative measurements would be needed in cases where the presence of brain atrophy might determine clinical decisions.

Assessment of brain atrophy by computer tomography (author's transl)

Computer tomograms from 512 patients with brain atrophy were analysed according to standardized criteria. Exact studies of the outer and inner CSF spaces allowed a redefinition of this disease entity. The limits of change related to the physiological process of aging were established. In addition, an attempt was made to correlate CT findings with EEG tracings and psychiatric criteria.